Thief is an undeniable classic for the PC platform, meshing well-realized, objective-based stealth gameplay with dark fantasy elements and a consistently unsettling atmosphere to provide an amazing experience on every front. Basically, you were sneaking through a huge variety of locations (from haunted crypts to mage towers to castles to churches), discreetly knocking out guards so you could slip through, using clever gadgets like water arrows, rope arrows, flash bombs and gas mines, and stuffing anything valuable into your pockets for later use while staying one step ahead of monster and guard alike. In short, it's one of the best games ever made.
The Dark Mod is a fan-made spiritual successor to that style of gameplay, running on id Tech 4 (the engine of Doom 3) and carrying on its overall style very well - the engine lends itself to moody lighting and surprisingly sophisticated enemy AI, and while the physics are slightly clumsy, they capture the feel of classic Thief almost perfectly. Things are changed up a bit, though; the lockpicking is more of a timing-based minigame and there is no running storyline (unsurprising, as most of the levels are standalone fan-made missions). Still, fans of Thief's gameplay should have a lot to like here; there are dozens of fan-made missions available, and all of it is, of course, completely free.
Information on exactly how it's done is inconsistent across the internet (and seemingly in the game too), but what got it for me was:
Lure rod with a Fork is required, so you will need to recruit Olivie first.
Heim Rada hot springs between 4-9 PM (save at 3:30 or so, then reload if you miss it)
The way the Lure Rod works is that you have to input combinations of movements to catch specific fish. This time it was pressing Left-Right four times, reeling for about one second, and then repeating until he bites.
Once he does, hit Down on the analog stick to snag him, then just reel him in like you would any other fish. It can be done even with a completely non-upgraded Lure Rod (which I did here), but do be careful not to snap your line. Tap the button to reel him in bit by bit and tap the direction of the arrow when it pops up to reduce tension. It'll take about 2-3 minutes, but be patient and you'll get him.
Unfortunately it seems this fish is useless for any future races. Once you win a prize with a fish it can't race again, and there seems to be a hard upper limit on how many points you have on any single fish (about 400). Once you go above that threshold, the game freezes.
So now she just resides in my tank as a trophy commemorating the triumph of genetic engineering.